【英文原文】

Prevent computer eyestrain

Sit at least 20 inches away from the screen, and place it at or slightly below eye level.
Follow the 20／20／20 rule：every 20 minutes, focus on something at least 20 feet away for 20 seconds.
Post a reminder near your screen that says BLINK. Research shows we blink far less often when staring at a computer, and that’s a major contributor to eyestrain.

来源:可可英语 http://www.kekenet.com/Article/201006/105706.shtml